The start-up is capitalizing on a recent surge in valuations of social media, networking and local online companies including Facebook, LinkedIn, Yelp and Twitter

SAN FRANCISCO -- Nextdoor said Tuesday it raised $60 million in a funding round led by new investors, John Doerr and Mary Meeker of Kleiner Perkins and Lee Fixel of Tiger Global, to help the neighborhood networking start-up expand outside the U.S.

The round also included Comcast Ventures, as well as previous investors, Benchmark, Greylock Partners, and Shasta Ventures.

Nextdoor, co-founded and led by CEO Nirav Tolia, lets neighbors create private websites where they get to know one another, ask questions, exchange local advice and recommendations, and organize virtual neighborhood watches to reduce crime.

The firm started two years ago and about 5,000 neighborhoods joined the platform in the first year. That has jumped to about 23,000 neighborhoods now, which Nextdoor estimates is one in seven neighborhoods in the U.S.

Nextdoor had already raised $21.6 million in February and $18.6 million in 2012 and Tolia said it has only spent about $10 million of that. However, the company is capitalizing on a recent surge in valuations of social media, networking and local online companies including Facebook, LinkedIn, Yelp and Twitter, which is set to go public Nov. 7.

"The neighborhood is one of the original social networks," said Doerr. "The Nextdoor team is well positioned to create an enduring company at the intersection of social, local, and mobile."

Doerr will be an adviser to Nextdoor and will attend board meetings, although he won't become a director, Tolia said.

Tolia declined to disclose Nextdoor's valuation, although he said it was below $1 billion but still "very healthy."

Nextdoor will use its $90 million cash hoard to hire more engineers, designers and product specialists and expand outside the U.S. - something that Tiger Global's Fixel specializes in.

Nextdoor is still focused on user growth, rather than ways of generating revenue. However, Tolia said the company is thinking about ways to monetize its business in the future. One idea is group purchasing for neighborhood services such as pool cleaning, gardening and window cleaning, he said.